This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 11-334849, filed Nov. 25, 1999, the entire contents of which are incorporated herein by reference.
1. Field of the Invention
The present invention relates to a defect inspection data processing system for processing data obtained from defect inspection on a surface of a semiconductor wafer or a liquid crystal glass substrate, etc.
2. Description of the Related Art
In general, while a semiconductor wafer or a liquid crystal glass substrate is being manufactured, a patterned resist is provided on a silicon or glass substrate with a film interposed therebetween.
If, in such a photolithography process, the resist on the substrate is uneven in thickness or dust is adhered thereto, defects, such as uneveness in the line width of a pattern after etching, or occurrence of pinholes, may occur.
To avoid this, in a substrate manufacturing process before etching, all substrates are usually subjected to an inspection for detecting a defect. As a method for inspecting all substrates, a method of workers visually checking the substrates is often employed. However, when using workers to visually inspect the substrates, the dissimilarity in the checking ability of each worker, as well as the influence of dust from the bodies of workers in a clean room cannot be ignored. In light of this, a method for observing substrates at as far a distance as possible, or a method for imparting a defect inspecting function to an apparatus is proposed.
FIG. 4 is a view illustrating an example of a defect inspection apparatus for detecting a defect on a surface of a to-be-inspected object, disclosed in Japanese Patent Application KOKAI Publication No. 09-061365. An illumination section 101 has an illumination light source and an optical system. As the illumination light source, a lamp housing is used which contains a halogen lamp, a heat-wave absorbing filter and a condenser lens. Further, the optical illumination system comprises a condenser lens for converging a light flux from the lamp housing and a fiber bundle.
The illumination section 101 emits illumination light to a to-be-inspected object 105 at incident angle xcex80. A cylindrical lens 103 for converging a light flux is interposed between the illumination section 101 and the to-be-inspected object 105. A line sensor camera 104 is provided in a position opposed to the illumination section 101. The line sensor camera 104 picks up an image of a linear area of the illuminated object 105.
The to-be-inspected object 105 is moved in a direction indicated by the arrow in the figure, and an image picked up by the line sensor camera 104 in synchronism with the movement is supplied to an image pickup circuit 102. The image pickup circuit 102 forms a two-dimensional image and supplies it to a host computer (not shown). The line sensor camera 104 has a structure that enables the angle between the camera and the surface of the to-be-inspected object 105 to be changed. For example, if the angle is set equal to the reflection angle xcex81 of the illumination section 101, the surface of the to-be-inspected object 105 can be picked up.
After that, images of the to-be-inspected object 105, picked up in synchronism with the movement of the object, with the reflection angle of the illumination section 101 set at xcex80xe2x80x2 (=xcex80) and xcex81, are subjected to image processing by the host computer. As a result, a defect such as the unevenness of a film on the to-be-inspected object 105 or dust attached thereto is extracted and compared with an acceptability criterion that is one of the inspection conditions, thereby determining whether or not the to-be-inspected object 105 is defective.
In the above-described defect inspection apparatus, a defect image pickup section including the illumination section 101 and the line sensor camera 104 is connected to the host computer for determining, for example, whether or not the to-be-inspected object is defective. The defect inspection apparatus including the defect image pickup section and host computer are installed in a clean room. In the clean room, air is downwardly flown from an upper portion of the room through an air-cleaning filter, thereby preventing, for example, dust particles from adhering to the to-be-inspected object and hence the influence of the dust particles upon defect inspection.
However, in the above structure, one computer is provided for one defect image pickup section. Therefore, if a plurality of defect inspection apparatuses are prepared to increase the inspection efficiency, it is necessary to accommodate the same number of defect image pickup sections and host computers in the clean room. This means that the clean room must be large. Accordingly, the entire equipment involves an increase in costs, which is economically disadvantageous. Furthermore, since other apparatuses including the host computer are located in the clean room, together with the defect image pickup section, workers come into and out of the clean room, which limits the dust preventing effect.
Where a defect inspection apparatus is provided for each process executed in the clean room, different inspectors operate host computers respectively connected to different defect inspection apparatuses. Since the inspectors usually have different criterions for defect determination, the accuracy of the entire defect inspection is reduced. Also, where clean rooms are located along the manufacture lines of respective factories remote from each other, it is very possible that different criterions will be used for defect inspection in different factories. As a result, the efficiency and accuracy of defect inspection are reduced.
It is the object of the invention to provide an economical and compact defect inspection data processing system that enables a plurality of defect inspection apparatuses to execute efficient and accurate defect inspection.
(1) A defect inspection data processing system according to the invention comprises: a client computer including image pickup means for picking up a two-dimensional image of a to-be-inspected object to be processed in a manufacturing process, and data transfer means for transferring data indicative of the image picked by the image pickup means; a database for storing image data transferred from the client computer; and a host computer including defect extraction means for extracting defect information from the image data read from the database, and good/bad judgment means for judging whether or not the to-be-inspected object is good, on the basis of the defect information extracted by the defect extraction means, the client computer being separate from the host computer and connected thereto via a communication line.
(2) The defect inspection data processing system of the present invention is a system according to item (1), in which the good/bad judgment means has a function of comparing the defect information extracted by the defect extraction means with defect data registered in a predetermined defect dictionary, thereby determining the type of defect, and a function of registering new defect data in the defect dictionary.
(3) The defect inspection data processing system of the present invention is a system according to item (1), in which the database is connected to the communication line, thereby storing, in the database, image data transmitted thereto from the client computer via the communication line, and transferring the image data, stored in the database, to the host computer via the communication line.
(4) The defect inspection data processing system of the present invention is a system according to item (1), in which the communication line is connected to a plurality of client computers.
(5) The defect inspection data processing system of the present invention is a system according to item (3), in which the communication line is connected to a plurality of client computers.
(6) The defect inspection data processing system of the present invention is a system according to item (1) or (3), in which the host computer is located in a place different from a place in which the client computer is located, the host and client computers being connected via the communication line.
(7) The defect inspection data processing system of the present invention is a system according to item (1) or (3), in which the client computer is located in a clean room for executing the manufacturing process, and the host computer is located outside the clean room and separate from the client computer.
(8) The defect inspection data processing system of the present invention is a system according to item (4), in which the plurality of client computers are located in different areas and connected to the host computer via the communication line.
(9) The defect inspection data processing system of the present invention is a system according to item (1), in which the client computer includes defect extraction means for extracting a defective portion from image data picked by the image pickup means.
(10) The defect inspection data processing system of the present invention is a system according to any one of items (3), (4) and (5), in which the client computer includes defect extraction means for extracting a defective portion from image data picked by the image pickup means.
(11) The defect inspection data processing system of the present invention is a system according to item (1), in which the host computer includes an image storage for storing image data picked by the image pickup means, and a defect detection algorism formed of a plurality of defect extraction means for processing, in a parallel manner, a plurality of different image data items stored in the image storage.
(12) The defect inspection data processing system of the present invention is a system according to any one of item (1), (9) and (11), in which the defect extraction means includes image nonuniformity removing means for removing image nonuniformity from the image data.
(13) The defect inspection data processing system of the present invention is a system according to item (10), in which the defect extraction means includes image nonuniformity removing means for removing image nonuniformity from the image data.
(14) The defect inspection data processing system of the present invention is a system according to item (12), in which the image nonuniformity removing means includes image nonuniformity storage means for acquiring, from the image pickup means, a sample image having a nondefective mirror surface or having a uniform reflectance over an entire surface thereof, and storing image nonuniformity data on the sample image, the image nonuniformity removing means removing the image nonuniformity data from image data read from the database.
(15) The defect inspection data processing system of the present invention is a system according to any one of item (1), (9) and (11), in which the defect extraction means further includes feature storage means for storing an image and coordinates of a characterizing portion of the to-be-inspected object, which determines coordinates of the to-be-inspected object, characterizing-portion-extracting means for comparing an image, stored in the feature storage means, with image data read from the database, thereby obtaining a displacement therebetween, and image position correcting means for correcting the image displacement detected by the characterizing-portion-extracting means.
(16) The defect inspection data processing system of the present invention is a system according to item (10), in which the defect extraction means further includes feature storage means for storing an image and coordinates of a characterizing portion of the to-be-inspected object, which determines coordinates of the to-be-inspected object, characterizing-portion-extracting means for comparing an image, stored in the feature storage means, with image data read from the database, thereby obtaining a displacement therebetween, and image position correcting means for correcting the image displacement detected by the characterizing-portion-extracting means.
(17) The defect inspection data processing system of the present invention is a system according to item (1), in which the communication line is connected to operation/input means for supplying an instruction to the client computer by remote control.
(18) The defect inspection data processing system of the present invention is a system according to item (1), in which the host computer automatically stores, in the database, image data determined defective by the good/bad judgment means.
(19) The defect inspection data processing system of the present invention is a system according to item (1), in which the image pickup means is formed of a line illumination unit and a line sensor camera, which can move relative to the to-be-inspected object to obtain an image of an entire surface of the to-be-inspected object, an angle of an optical axis of each of the line illumination unit and the line sensor camera relative to the surface of the to-be-inspected object being able to be changed to obtain different image data items.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.